consUnique is package {
  R is relation{
        { F="U"};
  }

  constCons has type ((%a) => cons of string);
  constCons(l) is cons of {"a"};

  foo is
    let {
      routeOperationNames is unique x.F where x in R order by x.F;
    } in 
      constCons(routeOperationNames);
  
  main() do {
    logMsg(info,"$foo");
  }
}